Indexable circular cutting insert

Abstract

An indexable, invertable cutting insert has radially-oriented positioning segments on a front face of the insert and radially-oriented positioning segments on the back face of the insert. The radially-oriented positioning segments are shifted on the front face relative to those on the back face such that, when the cutting insert is engaged within the toolholder, the cutting segment utilized on the front face will never be directly opposite the cutting segment utilized on the back face. A toolholder system is made up of the cutting insert and a toolholder capable of securing and indexing the cutting insert.

The invention claimed is: 
     
       1. An indexable cutting insert having a generally cylindrically shaped body with a central longitudinal axis extending therethrough, wherein the generally cylindrically shaped body has:
 a front face, an opposing back face, and a side wall therebetween; 
 a front cutting edge at the intersection of the sidewall and the front face; 
 c) a back cutting edge at the intersection of the sidewall and the back face; 
 a plurality of front positioning segments on the front face, wherein the front positioning segments have centerlines and, wherein the centerlines of adjacent front positioning segments define evenly spaced radial angles RA about the central longitudinal axis for indexing the cutting insert within a toolholder; 
 a plurality of back positioning segments on the back face, wherein the back segments have centerlines and wherein the centerlines of adjacent back positioning segments define evenly spaced radial angles RB about the central longitudinal axis for indexing the insert within a toolholder; 
 wherein the front positioning segments and the back positioning segments are projections extending from or indentations extending into the respective faces intended to engage the pocket of a toolholder, 
 wherein the centerlines of the back positioning segments, when projected along the central longitudinal axis through the body onto the front face, bisect the radial angles RA defining the front positioning segments, 
 wherein distinct cutting sections are defined between the positioning segments such that the cutting sections on the front face of the cutting insert are radially shifted about the longitudinal axis from the cutting sections on the back face of the cutting insert, 
 wherein the front positioning segments and the back positioning segments include indicia thereupon to uniquely identify each distinct cutting section for the purpose of indexing the cutting insert within the toolholder to avoid reusing a previously used cutting section, 
 wherein the front face has a floor that is radially inward and lower in elevation with respect to the front cutting edge, and 
 wherein the back face has a floor that is radially inward and lower in elevation with respect to the back cutting edge, and 
 wherein the front positioning segments extend from or into the floor of the front face such that the front positioning segments are not higher in elevation than the front cutting edge, and 
 wherein the back positioning segments extend from or into the floor of the back face such that the back positioning segments are not higher in elevation than the back cutting edge. 
 
     
     
       2. The cutting insert according to  claim 1 , further comprising a sloped wall extending between the front and back cutting edges and the floor. 
     
     
       3. The cutting insert according to  claim 1 , wherein the front positioning segments and the back positioning segments are generally U-shaped. 
     
     
       4. The cutting insert according to  claim 1 , wherein the indicia are numbers. 
     
     
       5. The cutting insert according to  claim 1 , wherein the radial angles RA formed on the front face have equal increments to the radial angles RB formed on the back face. 
     
     
       6. The cutting insert according to  claim 1 , wherein the body has a central bore extending therethrough along the longitudinal central axis to accommodate a hold-down bolt for securing the body to a toolholder. 
     
     
       7. The cutting insert according to  claim 1 , wherein there are four positioning segments on the front face and four positioning segments on the back face of the body, wherein each segment forms an angle of 90 degrees with an adjacent segment on the respective face. 
     
     
       8. The cutting insert according to  claim 1 , wherein there are six positioning segments on the front face and six positioning segments on the back face of the body, wherein each segment forms an angle of 60 degrees with an adjacent segment on the respective face. 
     
     
       9. The cutting insert according to  claim 1 , wherein there are eight positioning segments on the front face and eight positioning segments on the back face of the body, wherein each segment forms an angle of 45 degrees with an adjacent segment on the respective face.